1. Field of the invention
This invention relates generally to the application of marking lines of contrast coloured material such as strips of synthetic resin paint to road surfaces for the guidance of traffic.
2. Description of the prior art
It is well-known in the art to apply such strip-shaped lines by means of spray painting, the paint being supplied to a spray nozzle on a carriage moved along the road surface, the thickness of the paint strip being adjustable by means of a jet needle by which the nozzle can also be closed. According to another known method a narrow strip of tar was laid on the road surface by a tar sprayer which was followed by a grit spreader discharging white grit from a controlled slit-shaped opening, carried above and parallel to the road surface. By these known methods only strips of regular continuous thickness could be made, though this thickness could be adjusted to a value as desired.
It is also known per se in the prior art to enclose the traffic lanes on the road surface between prefabricated marking strips of concrete provided with parallel cross ribs following a zigzag course in their longitudinal direction, rather steep light-reflecting front faces of the ribs being directed at least by their upper portions against the headlights of approaching vehicles. In this known art the marking strip appeared, thanks to the close succession of these ribs to the oncoming traffic as a clearly visible, continuous, farstretching, shining strip even in dark and bad weather. Until now, however, it was very expensive to provide roads with such ideal marking lines and the application was restricted therefore to extremely dangerous road bends.
In the field of road construction a method has been proposed for the continuous construction of ribbed retaining beams along the sides of road pavements from concrete which is poured between the side walls of a bottomless mould which is moved along the side of the road surface and the ribs are formed on the surface of the beam by means of an outward and inward swinging movement of a hinged mould back wall, controlled by eccentrics or cranks on a rotating axle.
In still another field of the art, to be the art of providing a prefabricated band with a ribbed or knurled surface of a snowy or lump-forming material it has been proposed to use the band as the bottom of a bottomless storage box comprising the said material, this band being moved relatively along the bottomside of the boxframe e.g. by unwinding it from a reel; an oscillatory up- and down movement being imparted to the back wall of the box so that the lower edge of the said wall will shape a ribbed or knurled surface of the material left behind upon the prefabricated band, a knurled shape being obtained by providing the said wall with a toothed lower edge.